The challenge of dealing with urban air pollution

When the UK passed the Clean Air Act in 1956 to reduce smoke and sulphur dioxide, it led the world in cleaning up air. In recent years air quality improvements have miserably stalled. We have been breaching European Union (EU) limit values every year since 2005 for the modern day pollutants nitrogen dioxide (NO2) and particulate matter (PM). Currently there is no prospect of achieving compliance for NO2 in some areas until 2025.

More worryingly, evidence to support the detrimental short and long-term effects on health has increased substantially over the same period of time. Data for 2008 estimate that air pollution contributes to at least 29,000 premature deaths in the UK each year.

In 2012, the International Agency for Research on Cancer classified particulates in diesel fumes as a known carcinogen. In 2013, a WHO report concluded that the health effects of PM and NO2 can occur at concentrations lower than the their health-based Guideline values which of note, are lower than the EU limits we fail to adhere to.

In addition, other than the well-documented risks to cardiopulmonary heath, increasing evidence exists that air pollution exerts a wider threat, negatively influencing reproductive outcomes and neurological health.

The lack of progress in improving air quality isn’t due to lack of attention by professionals in the field or lack awareness by Government. I and other expert witnesses have given evidence to the Commons Environmental Audit Committee in 2010 and again in 2011 – the ensuing reports were blatant in their conclusions, calling in 2010 for ‘political will’ and ‘committed resources to meet air quality targets.

The 2011 report concluded that ‘the Government has failed to get to grips with the issue’ and ‘must not continue to put the health of the nation at risk’. In February 2014 the European Commission launched legal proceedings against the UK for excessive emissions of NO2. This is the first case by the EU against a member state for breaching limits. One can only hope that this may have the clout to shake political indifference to air quality in this country.

Unlike the powers that be, up until the beginning of last week, it is probably fair to say that the majority of the public was relatively unaware of day-to-day air pollution, the sources and the dangers associated with current concentrations. This is partly because PM can’t be seen by the naked eye and NO2 is invisible and probably owing to a poor understanding of what is undisputedly a complex science.

However on Sunday 30 March 2014 light southeasterly winds began to blow Saharan dust plus polluted air from Europe over the UK. This mingled with our domestic emissions from cars and industry resulting in high levels of rather unusual mix of pollution. Owing to the persistence of easterly winds and dry weather, poor air quality remained with us until the end of the week.

Light easterly winds taking pollutants from continental Europe to the UK where are own fresh emissions are added is not unusual – even dust flows from the Sahara are not uncommon. Instead, what really grabbed the attention of the nation – other than the visible hazy smog – was the prolific reporting of the events in every conceivable form of media.

This was because on the 1 April 2014 the Met Office, our national weather service provider, took over responsibility for forecasting air pollution on behalf of Defra. With that came greater publicity. In comparison, previous episodes have attracted insignificant coverage. Other than registered users of proactive air pollution alert services, you would have been hard pressed to hear about the even worse poor air quality affecting parts of England three weeks ago. This particular event culminated in London recording the greatest concentration of PM10 in 2 years.

The highly charged media coverage did not stop even when air quality improved. This was the result of a change in wind direction to southwesterly, coming in from the cleaner Atlantic, combined with wet weather washing the pollutants out of the air. Sunday’s press covered emerging evidence that traffic-related air pollution may target neurodevelopment and cognitive function as well as holding diesel fumes to account.

British drivers respond to the marketing of diesel cars as the “green” option – on the basis of reduced CO2 emissions and lower fuel costs – such that approximately one half of all new private car registrations in 2012 were diesel. Added to this, in most cities diesel engines power the majority of our buses and taxis. The image however is now tarnished.

Diesel engines emit especially harmful particulate pollution and owing to lenient European testing regimens, NO2 emissions have risen steadily of the past 10-15 years. It was reassuring that this information reached the front pages of the Sunday broadsheets.

This pollution episode has certainly raised the profile of what, to many, has previously been an invisible problem. However the chronic effects of air pollution, owing to year-round exposure, are much more worrisome than the short-term, often transient outcomes. We cannot afford to just focus on distinct episodes. As succinctly put in one online blog earlier this week: ‘We need to reduce air pollution when it isn’t making the headlines as well as when it is.’ Traffic must be reduced and we must ensure a cleaner and greener element to what remains on the road.

This can be achieved through a number of strategies: an expansion of low emission zones, investment in clean and affordable public transport, a move back from diesel to petrol or at least a ban on all diesel vehicles not fitted with a particulate filter and a lowering of speed limits. Focused education and continued evolution of sophisticated information systems can also achieve a durable change in public attitude and in turn behaviour.

But engagement must be blatant and put in the context of other public health risks such as passive smoking and utilise compelling messages such as premature death. There will be costs – but these should be balanced against the economic cost from the impacts of air pollution in the UK that are estimated at £9-£19 billion every year.

Cracking our air pollution problem is a huge challenge. It is highly unlikely that our major cities will ever be able to boast ‘pure air’ especially if strategies focus on small areas of an overall road network – as I have been quoted before: ‘air pollution does not respect any boundaries’. With bold, realistic and moral leadership however, enormous potential exists to reduce air pollution so that it no longer poses a damaging and costly toll on public health.

One Response

Assuming that the UK is anything like the US (and I’m assuming it is), then air pollution may be the cause of increased heart disease among the poor and disenfranchised living in urban settings. This is based on a recent University of Minnesota report (http://www.sciencetime.org/blog/urban-air-quality) which found that minorities living in urban settings are more likely to suffer heart attacks as an exposed to higher levels of nitrogen dioxide.

Disclaimer

The aim of this blog is to encourage discussion and debate on public health issues. The views expressed here are the personal views of authors, and the content does not reflect the official position of the Faculty of Public Health. However, discussion generated here may be used to influence the development of organisational policy.